The issues included possible complaints about noise and vibration, trespass on the railway reserve, and safety.

The line carries about 18 trains each day, and there was potential for electrification and greater use in future.

Hewett said KiwiRail would not support any additional level crossings.

Level crossings manager Brett Williams said the crossings at James Line and Stoney Creek Rd already ranked at 136 and 144 out of 1244 level crossings around New Zealand on a risk assessment.

Although they rated "quite highly", they were not on an upgrade priority list yet.

Submitter Phil Pirie, a consultant surveyor speaking for several clients, said he was perplexed there were no plans to improve those rail crossings given the increased demands urban development would place on them.

Batley said regardless of possible improvements to the James Line and Stoney Creek Rd railway crossings, the underpass in the centre of the new suburb would be an important asset.

"They may require underpasses, but that is a separate traffic management problem." Without the central underpass, there would be no link between the suburb's upper and lower terraces.

"This is about connectivity, for people to go either from the lower terrace to other parts of Kelvin Grove where the supermarket and sports fields are located, or from the upper terrace to the school."

The hearings panel, chaired by commissioner Chris Mitchell, has closed the hearing and will consider its decision in private.